luminosity
n. C1 Advanced UK //lˌuːmɪnˈɒsɪti// lu·mi·nos·i·ty
n. the amount of light that an object gives off. In astronomy, it helps scientists measure how bright a star is compared to our sun.
n. the total amount of electromagnetic radiation emitted by an astronomical object per unit of time. Often used to describe the intrinsic brightness of a star or galaxy.
The star has a high luminosity.
Astronomers use luminosity to determine the distance to a galaxy by comparing its apparent brightness to its actual output.
While the star appears dim to the naked eye, its immense luminosity suggests it is a massive, young object located far beyond our solar system.
Borrowed from French luminosité or else a native formation from luminous + -ity.